Method of wireless signaling.



APPLICATION FILED JAN. 9, 1905.

Patented Sept. 30, 1913.

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inn can:

' .n'. A. PESSBNDEN.

METHOD OF WIRELESS SIGNALING AIlLICATION FILED JAN. 9, 1905.

1,074,423. Patented Sept. 30,1913.

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M 2 i 'g g Mg- I WHO??? 63 R. A. FBSSENDEN. METHOD OF WIRELESSSIGNALING.

APPLICATION FILED JAN.9, 1905.

1974, 123, V Patented Sept. 30, 1913.

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inaiirisn REGINALZ? A. FESSENIDEN, OF WASHINGTON, DISTRXCTQF (JGL'UMBIA,ASSIGNOEEL BY MESNE ASSIGNMENTS, TO SAMUEIi M. KINTNEIR. F- PITTSBURGH.'PI'JNNSYLV'ALI TIA, AND HALSEY M. BARRETT, 0T1 ELOOlVIFIELD, NEWJERSEY, RECEIVERS.

METHOD OF WIRELESS SIGNALING.

ose.

Specification of Letters Patent.

Application filed Ziamiary 9, 1905. Serial No. fi l-8,265.

To all whom it may concern v Be it known that l, lineman!) 1*Fisssrnnnn, residing at ashing'ton, in the District of Columbia, acitizen of the United States, have invented or discovered a certain newand useful Method of Wireless Signaling. of

in U. S. Patents 706,740 and 742,780.

In the accompanying drawings forming a part of this specificationFigures 1 and 7 are diagrammatic views illustrating receiving stationsconstructed in accoi'tlaz'ice with my improvement. Fig. 2 is a (lctailView illustrating the prefcrretl form of transformer. Figs. 3 and i areplan and sirle elevation respectively, illustrating the preferred formof adjustable capacity. Fig. illustrates another form of aliljustablccapacity. Fig. l5 shows in plan and elevation a desirable constructionof transformer. Fig. 8 .is a detail View snowing the construction of adisk employetl in the apparatus of Fig/7. and F 9 shows a motliticationof Fig. 1 with a condenser in place of coil 41.

In Fig. 11, l. a receiving antenna, grounded at l, and 5 representinductances adjustable by means ofthe sliding contacts 3 and 6, 7 and 8represent 'prii'naries and 9 and 10 secondariesof transformers, 11 and12 and 13 represent condensers, preferably adjustable. R The secondaries9 and 10 are preferably arranged in series with each other and inoperative relation to the receiver 17. The circuit including the sec--onclaries 9 and. 10 and the receiver preferably contains the variableinductances 14; and 14 and the adjustable condensers-15', 16 and 18. 19is an indicating inechanisn'i and 20 a potentiometer. 2-1 and 22 arecapacities for adjusting the capacity to ground. of'

a point on the receivingcircnit, preferably one of the terminals of thereceiver, though. both may beso connected, anti preferably consisting ofadjustable condensers connect eel to ground at the two are.

F 2 incl 6 showsuitable forms of transformers. In Fig. "2, 7 is aprimary anal 9 a secondary. The primary may consist for example of 100turns of #18 copper Wire \vounclon a glass jarQ l, live inches inoliameter and the secondary may consist o'l turns of L. Wire wound on aglass jar 25. six inches in diameter. The insideof the gar 1SPii'mffil'ilblJ covered with a conducting material 526 so or anged as toshield the secondary from electrostatic effects causecl by the-primarybut at the same time not to prevcnt electremagnetic inductive effectsbetween the two. One suitable method of arranging this is by paintingthe insitle of the jar with metallic paint such as bronze or gold paint.orbiy coating it with gold-leaf or by placing a cgrls indei" of copperslotted r This conduct" shield. may be connected to ground witlrgoodresults and the conducting; shields of both transformers maybe coniecterl together as shown in Fig. 7. The shied for the construction;

of transformer shown in 6 and 7 is indicated at inl igfll. A high resistcal 1 between ance or inductance 27 may be placed in the circuit togrouiuleth I a Another form of transformer is soown. in Fig". (3 ,Where29 are hard rubber rings gro nntl when the shield is having grooves cutin them and the pri-' mary wound in the groove one ring anal thesecondary wound in the groove of the other Theserings may also becoveretl with metallic paint or gold-foil or a. metallic disk 50radially slit may be placed between the two coils. This construction isespecially adapted for use where it is sired to obtain large inductancewith small capacity.

F and t show one form ofvariable condenser consisting of intercalatingmetal plates 30 and 31 preferably semicircular or approximately so incontour. Alternate plates are movable 111;21I1Cl out between the otherplates so that the one set of plates may be made to overlap the otherplates more or less as required. It is preferred to, secure the movableplates 31 to a shaft 32 provided with an operating handle. The shaft hasits axis coinciding with the center-of the arcsforining the perimetersof thegplatcs. so that by the rotation of the shatt'oiic set of platesmay be moved to a position in which they are entirely overlapped by theother plates and to a position in which there is not: any materialoverlapping of one set of plates by the other. One set of plates isinsulated from the other. A dial 34 and indicating linger 33 are soarranged that one or the other will be shifted with the movable plates.

Fig. 5 shows another form of variable uumberot turns. these turns may bealtered, as tor examplc'by the movable contacts tti.

amt IT. shown in Fig. 7. By sliding these onta ts the ircuits may' betuned by varying the inductance instead of l7 \-"\'2ll \lllg thecapacity. The primary 7 and the second- ::r v 9 may also be mademovable. relative to each other by sliding along the graduated arm 8 soas to vary the mutual inductance l)t'l.\\'tlll primaries andsecondaries, as shown in the. 7.

The, circuits 1, 9, S, 19-. 5, 13. 4 and 1, 2. 7, ll. 5, 13. t are tunedin such a way that when an impulse of the desircdperiodicity is receivedon the receiving conductdr, it generates strong: currents thwiugh one ofthese circuits: for example I; 2, S, 12, 5, 13, t but very wealvcurrents through the other and ccmscqueutly, the secondaries 9 and 10being wound in opposite directions the receiver 17 is stronglyall'ccted; but said circuits are so tuned that. impulses which have not.the desired periodicity will divide evenly through both circuits andconsequently produce equal and opposite effects which being thus neuti-alized, produce no efi'ect on the receiver. This is generallyaccomplished empirically and I have found asuitable method \v ould be toturn the variable capacity 11 to the position of zero capacity and totheu turn the variable capacity 12 until the maximum effect is producedby the waves it. is desired to receive. The variable capacity 11 is thenturned until the interfcring signals on disturbances are cut out.

It may happen that the neutralization cannot be rendered quite complete;on :10- count oi there being a phase diticrence in the currents flowingthrough the two primaries, and this is more especially aptto happen withinterference prcventers in which two transformers are used instead ofthree or four transformers. In order to innon-compensated voltageimpressed upon the secondaries 9 and 10 and opposite in direction. I donot limit myself to any specific method of effecting this compensationbut a suitable method is shown in Figpl where 38 and 30 are coils ininductive relation to each other and preferably capable of heineadjusted to different; distances apart by'agliidiug on the graduated arm40. Coil 38;l s in series with the secondaries 9 and 10 and coil 39 isoperatively connected to an 0 adjustable inductance ell, and vadjustableresistance l2. A current will therefore flow tln-pug'h the circuit 39,4t, 49., and the phase of this current can be altered by varying the adiust'ablc. inductance 41, which consists 5 i of two coils capable ofrelative angular nuivement or by changing the resistance 42 which ispret'erabl of very small capacity. The intensity ot the voltage whichwould be impressed on the circuit containing the secondaries 9. 1t) andthe coil 38 may be varied by varying the position of the coil 39.- Inthis way a voltage may be impressed on the circuit. of the secondaries 9and 10 which will have the proper phase and the proper value toneutralize the unbalanced componentof the interfering signals ordisturbances. Many other ways will suggest themselves of accomplishingthis result. For eX- ample the phase compensator may be induC- tivelyconnected to the vertical instead of directly connected. as shown inFig. 7. Also a variable capacity 49 may be substituted for the variableinductance 'tl, as shown in Fig.

9. in which case a leading current will be obtained instead of a laggingone, and the winding of the coil 39 must be reversed.

Theconnections of the coil 39 may be so arranged that they may bechanged by means of a switch shown at; 43 according as the unbalancedcomponent is a leading or lagging one.

It has -been experimentally demonstrated by the applicant that themethod 'of pros tecting a'receiver from undesired eflects, as

described herein, may without alteration be em loyed in'wire'telegraphy,and it will be un erstood that the claims are not limited to signalingby electro-magnetic waves.

' lVliile I have shown and described with same particularity apparatusapplicable to the practice of my improved method, no

claim is made herein to such apparatuses the same forms thesubject-matter of an application filed January (3th, 1906, Ser. No.

I claim herein as my invention- 1. In a system of signaling by periodicimpulses, the metliod of increasing the efliciency of the signalingbycausing the re- 13o 20 ceived impulses to flow through the primaceivedimpulses td flow through the primaries of two transformers and varyingthe inductive relation between the primaries and secondaries of saidtransformers.

2. In the art of signaling by periodic impulses, the method ofincreasing the efficiency of the signaling which comprises passing thereceived signal impulses through the primaries of two transformers,varying the inductive relation between said primaries and thesecondaries of the transformers to increase the resonance etfectspeculiar to the wave length being received, and adjusting the phase ofthe currents in the two transformers, to thereby neutralize the effectsof undesired currents on the secondaries, substantially as described.

3. In a system of signaling by periodic impulses, the method ofincreasing the efliciency of the signaling by causing the reries of twotransformers and through variable condensers and varying the inductiverelation between. the primaries and secondaries of said transformers,and shifting the 25 phase of the current in one of said transformers,substantially as described.

4. In electric signaling, the method which comprises passing receivedcurrents through a primary to induce currents in a secondary, 30 andcompensating the currents in the secondary.

5. In the art of signaling by periodic impulses, the method ofpreventing undesired impulses from affecting the receiver, 35.

which includes passing the received impulses through the primary of atransformer and inducing them into a receivercireuit connected with thesecondary of said transformer, and electrostatically shielding the 40said primary from said secondary, substantially as described.

In testimony whereof, I have hereunto set my hand.

REGINALD A. FESSENDEN. Witnesses:

CHARLES BARNETT, HERBERT BRADLEY.

